Me too. I always thought it would have been better if humans' processing cycles (thoughts) were utilised to supplement, validate and expand the Matrix. A sort of automatic, involuntary, unaware Mechanical Turk.

I think it's a better and more terrifying plot if you watch it as a Kafka-esque dystopia where people are imprisoned by the machines for inscrutable reasons that no-one truly knows. Morpheus's power supply theory is then just a necessary rationalization and a part of the mythology that allows the resistance to continue, while being fundamentally incorrect.

Thermodynamic impossibility is a relatively minor obstacle for a true believer.